Collecting data and monitoring workload performance

Unified Manager collects and analyzes workload activity every 5 minutes to identify performance events, and it detects configuration changes every 15 minutes. It retains a maximum of 30 days of 5-minute historical performance and event data, and it uses this data to forecast the expected range for all monitored workloads.

Note: This chapter describes how dynamic thresholds work and how they are used to help monitor workload performance. This chapter is not applicable for statistics or events caused by user-defined or system-defined performance threshold breaches.

Unified Manager must collect a minimum of 3 days of workload activity before it can begin its analysis and before the expected range for I/O response time and operations can be displayed on the Performance/Volume Details page and in the Dynamic Threshold Event Details page. While this activity is being collected, the expected range does not display all changes occurring from workload activity. After collecting 3 days of activity, Unified Manager adjusts the expected range, every 24 hours at 12:00 a.m., to reflect workload activity changes and establish a more accurate performance threshold.

During the first 4 days that Unified Manager is monitoring a volume, if more than 24 hours have passed since the last data collection, the charts on the Performance/Volume Details page will not display the expected range for that volume. Events detected prior to the last collection are still available.

Note: Daylight savings time (DST) changes the system time, which alters the expected range of
performance statistics for monitored workloads. Unified Manager
immediately begins to correct the expected range, which takes approximately 15 days to complete. During this time you can
continue to use Unified Manager, but, since Unified Manager
uses the expected range to detect events, some events might
not be accurate. Events detected prior to the time change are
not affected. Manually changing the time on a cluster, or on a Unified Manager server, to an earlier time will also affect the event analysis results.

More information

Workload performance measurement valuesUnified Manager measures the performance of workloads on a cluster based on historical and expected statistical values, which form the expected range of values for the workloads. It compares the actual workload statistical values to the expected range to determine when workload performance is too high or too low. A workload that is not performing as expected triggers a performance event report to notify you.

What the expected range of performance isThe expected range of values is a forecast, or prediction, of what the upper and lower performance values are expected to be at a specific time. For the workload latency, the upper values form the performance threshold. When the actual value crosses the performance threshold, Unified Manager triggers a performance event alert.

How the expected range is used in performance analysis Unified Manager uses the expected range to represent the typical I/O latency (response time) and IOPS (operations) activity for your monitored workloads. It alerts you when the actual latency for a workload is above the upper bounds of the expected range, which triggers a performance event, so that you can analyze the performance issue and take corrective action for resolving it.

How cluster operations can affect workload latency
Operations (IOPS) represent the activity of all user-defined and system-defined workloads on a cluster. The IOPS statistics help you determine whether cluster processes, such as making backups or running deduplication, are impacting workload latency (response time) or might have caused, or contributed to, a performance event.

Performance monitoring of MetroCluster configurationsUnified Manager enables you to monitor the write throughput between clusters in a MetroCluster configuration to identify workloads with a high amount of write throughput. If these high-performing workloads are causing other volumes on the local cluster to have high I/O response times, Unified Manager triggers performance events to notify you.

What performance events are
Performance events are incidents or configuration changes related to workload performance on a cluster. They help you identify workloads with slow response times and cluster configuration changes that might have caused or contributed to the slow response times.